Clients

Add clients from the Clients tab, from Add new (top right, on any screen), or right inside a new estimate or invoice with + New.
Each client has a phone, email, address, lead source, status (starts as Lead), and notes.
Next follow-up: set a date and it shows on the dashboard under Needs your attention when it comes due.
Each client shows what you've invoiced, what they've paid, and what they owe.